Release me Telkom

Telkom is holding me ransom. I canceled my Fibre account with them on the 12 September, on the 19 September my services were disconnected! On the 7th October I receive a statement due to pay full amount (R720),how do I pay full amount when I never had internet from the 19th September?? On top of that they haven't released my line so I can have another service provider to connect me. Why is Telkom holding me ransom??